blocks|key|103699|text|什么时候使用%25w[...]而不是常规数组？我相信你可以通过看着这两个，然后输入它们，然后思考你刚刚做了什么，就能想出原因。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|103700|当您有一个要转换为数组的单个单词列表时，请使用%25w[...]。当我有要循环遍历的参数，或者我知道将来要添加的命令时，我会使用它，因为%25w[...]使向数组添加新元素变得很容易。在阵列的定义中有较少的视觉噪声。|103701|当您的元素中嵌入了会欺骗%25w的空格时，请使用常规字符串数组。对于必须包含非字符串元素的数组，请使用它。用逗号将"和'中的元素括起来会产生视觉噪声，但这也使得创建任何对象类型的数组成为可能。|103702|因此，您可以选择何时使用其中之一，当它对您最有意义时。它被称为“程序员的选择”。|103703|entityMap^0|6|7|0|N|7|1U|7|0|C|2|1J|1|1L|1|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Q|8|@$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]|$9|10|A|11|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|12|8|@]|D|@]|E|$]]|$1|L|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|M|$]]

When to use <code>%w[...]</code> vs. a regular array? I'm sure you can think up reasons simply by looking at the two, and then typing them in, and thinking about what you just did.

Use <code>%w[...]</code> when you have a list of single words you want to turn into an array. I use it when I have parameters I want to loop over, or commands I know I'll want to add to in the future, because <code>%w[...]</code> makes it easy to add new elements to the array. There's less visual noise in the definition of the array.

Use a regular array of strings when you have elements that have embedded white-space that would trick <code>%w</code>. Use it for arrays that have to contain elements that are not strings. Enclosing the elements inside <code>"</code> and <code>'</code> with intervening commas causes visual-noise, but it also makes it possible to create arrays with any object type. 

So, you pick when to use one or the other when it makes the most sense to you. It's called "programmer's choice".

blocks|key|320581|text|正如您正确指出的那样，它们会产生相同的结果。所以，在做决定时，选择一个能产生更简单代码的代码。在本例中，它是%25w操作符。在您的previous+question中，它是数组文字。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|320582|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/q/16476628/125816^0|1I|2|1R|H|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

As you correctly noted, they generate the same result. So, when deciding, choose one that produces simpler code. In this case, it's the <code>%w</code> operator. In the case of your <a href="https://stackoverflow.com/q/16476628/125816">previous question</a>, it's the array literal.

blocks|key|103753|text|使用%25w可以避免在字符串两边使用引号。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|103754|此外，还有更多这样的快捷方式：|103755|%25W+-+double+quotes
%25r+-+regular+expression++
%25q+-+single-quoted+string
%25Q+-+double-quoted+string
%25x+-+shell+command|code-block|syntax|javascript|103756|有关更多信息，请参阅"What+does+%25w(array)+mean?“|103757|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/1274675/ruby-what-does-warray-mean^0|2|2|0|0|0|B|P|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|11|8|@]|D|@$9|12|A|13|1|14]]|E|$]]|$1|O|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

Using <code>%w</code> allows you to avoid using quotes around strings.

Moreover, there are more shortcuts like these:

<pre><code>%W - double quotes
%r - regular expression 
%q - single-quoted string
%Q - double-quoted string
%x - shell command
</code></pre>

More information is available in "<a href="https://stackoverflow.com/questions/1274675/ruby-what-does-warray-mean">What does %w(array) mean?</a>"

blocks|key|103868|text|这是我记忆中的方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|103869|%25Q/%25q用于字符串|103870|%25Q用于双引号字符串(适用于字符串中有多个引号字符时)。|103871|而不是这样做：|103872|“I+said+\“Hello+World\””|code-block|syntax|javascript|103873|您可以执行以下操作：|103874|%25Q{I+said+“Hello+World”}|103875|%25q用于单引号字符串(请记住，单引号字符串不支持字符串插值或转义序列，例如\n。当我说不支持时，我的意思是单引号字符串需要将转义序列作为特殊字符处理，换句话说，转义序列将只是字符串文字的一部分)|103876|103877|‘I+said+\’Hello+World\’’|103878|103879|%25q{I+said+'Hello+World'}|103880|但请注意，如果字符串中有一个转义序列，则不会对其进行处理，而是将其视为文字反斜杠和n字符：|103881|result+=+%25q{I+said+Hello+World\n}
+=>+"I+said+Hello+World\\n"+
puts+result
I+said+Hello+World\n|103882|请注意，文字\n未被视为换行符，但它带有%25Q：|103883|result+=++%25Q{I+said+Hello+World\n}
+=>+"I+said+Hello+World\n"+
puts+result
I+said+Hello+World|103884|%25W/%25w用于数组元素|103885|%25W用于双引号数组元素。这意味着它将支持字符串插值和转义序列：|103886|103887|orange+=+"orange"
result+=+["apple",+"#{orange}",+"grapes"]
+=>+["apple",+"orange",+"grapes”]|103888|您可以这样做：|103889|result+=+%25W(apple+#{orange}+grapes\n)
+=>+["apple",+"orange",+"grapes\n"]+
puts+result
apple
orange
grapes|103890|请注意，转义序列\n导致在grapes之后换行。%25w不会发生这种情况。%25w用于单引号的数组元素。当然，单引号字符串不支持插值和转义序列。|103891|103892|result+=+[‘a’,+‘b’,+‘c’]|103893|103894|result+=+%25w{a+b+c}|103895|但是看看当我们尝试这个的时候会发生什么：|103896|result+=+%25w{a+b+c\n}
+=>+["a",+"b",+"c\\n"]+
puts+result
a
b
c\n|103897|请记住，不要将这些结构与%25x+(用于运行unix命令的`反引号的替代)、%25r+(当您的正则表达式中有很多/字符并且不想转义它们时使用的//正则表达式语法)以及最后的%25s+(用于符号)混淆。|103898|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1X|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1Z|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|20|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|21|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|22|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|23|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|24|8|@]|9|@]|A|$]]|$1|S|3|G|5|6|7|25|8|@]|9|@]|A|$]]|$1|T|3|U|5|J|7|26|8|@]|9|@]|A|$K|L]]|$1|V|3|N|5|6|7|27|8|@]|9|@]|A|$]]|$1|W|3|X|5|J|7|28|8|@]|9|@]|A|$K|L]]|$1|Y|3|Z|5|6|7|29|8|@]|9|@]|A|$]]|$1|10|3|11|5|J|7|2A|8|@]|9|@]|A|$K|L]]|$1|12|3|13|5|6|7|2B|8|@]|9|@]|A|$]]|$1|14|3|15|5|J|7|2C|8|@]|9|@]|A|$K|L]]|$1|16|3|17|5|6|7|2D|8|@]|9|@]|A|$]]|$1|18|3|19|5|6|7|2E|8|@]|9|@]|A|$]]|$1|1A|3|G|5|6|7|2F|8|@]|9|@]|A|$]]|$1|1B|3|1C|5|J|7|2G|8|@]|9|@]|A|$K|L]]|$1|1D|3|1E|5|6|7|2H|8|@]|9|@]|A|$]]|$1|1F|3|1G|5|J|7|2I|8|@]|9|@]|A|$K|L]]|$1|1H|3|1I|5|6|7|2J|8|@]|9|@]|A|$]]|$1|1J|3|G|5|6|7|2K|8|@]|9|@]|A|$]]|$1|1K|3|1L|5|J|7|2L|8|@]|9|@]|A|$K|L]]|$1|1M|3|N|5|6|7|2M|8|@]|9|@]|A|$]]|$1|1N|3|1O|5|J|7|2N|8|@]|9|@]|A|$K|L]]|$1|1P|3|1Q|5|6|7|2O|8|@]|9|@]|A|$]]|$1|1R|3|1S|5|J|7|2P|8|@]|9|@]|A|$K|L]]|$1|1T|3|1U|5|6|7|2Q|8|@]|9|@]|A|$]]|$1|1V|3|-4|5|6|7|2R|8|@]|9|@]|A|$]]]|1W|$]]

This is the way I remember it:

%Q/%q is for strings

%Q is for double-quoted strings (useful for when you have multiple quote characters in a string). 

Instead of doing this:

<pre><code>“I said \“Hello World\””
</code></pre>

You can do:

<pre><code>%Q{I said “Hello World”}
</code></pre>

%q is for single-quoted strings (remember single quoted strings do not support string interpolation or escape sequences e.g. \n. And when I say does not "support", I mean that single quoted strings will need process the escape sequence as a special character, in other words, the escape sequence will just be part of the string literal)

Instead of doing this:

<pre><code>‘I said \’Hello World\’’
</code></pre>

You can do:

<pre><code>%q{I said 'Hello World'}
</code></pre>

But note that if you have an escape sequence in string, that will not be processed and instead treated as a literal backslash and n character:

<pre><code>result = %q{I said Hello World\n}
 =&gt; "I said Hello World\\n" 
puts result
I said Hello World\n
</code></pre>

Notice the literal \n was not treated as a line break, but it is with %Q:

<pre><code>result = %Q{I said Hello World\n}
 =&gt; "I said Hello World\n" 
puts result
I said Hello World
</code></pre>

%W/%w is for array elements

%W is used for double-quoted array elements. This means that it will support string interpolation and escape sequences:

Instead of doing this:

<pre><code>orange = "orange"
result = ["apple", "#{orange}", "grapes"]
 =&gt; ["apple", "orange", "grapes”]
</code></pre>

you can do this:

<pre><code>result = %W(apple #{orange} grapes\n)
 =&gt; ["apple", "orange", "grapes\n"] 
puts result
apple
orange
grapes
</code></pre>

Notice the escape sequence \n caused a newline break after grapes. That would not happen with %w. %w is used for single-quoted array elements. And of course single quoted strings do not support interpolation and escape sequences.

Instead of doing this:

<pre><code>result = [‘a’, ‘b’, ‘c’]
</code></pre>

you can do:

<pre><code>result = %w{a b c}
</code></pre>

But look what happens when we try this:

<pre><code>result = %w{a b c\n}
 =&gt; ["a", "b", "c\\n"] 
puts result
a
b
c\n
</code></pre>

Remember do not confuse these constructs with %x (alternative for ` backtick which is used to run unix commands), %r (alternative for // regular expression syntax useful when you have a lot of / characters in your regular expressions and do not want to escape them) and finally %s (which is sued for symbols).

The following two statements will generate the same result:

<pre><code>arr = %w(abc def ghi jkl)
</code></pre>

and 

<pre><code>arr = ["abc", "def", "ghi", "jkl"]
</code></pre>

In which cases should <code>%w</code> be used?

In the case above, I want an array <code>["abc", "def", "ghi", "jkl"]</code>. Which is the ideal way: the former (with <code>%w</code>) or the later?

When to use %w?

以下两条语句将生成相同的结果：arr = %w(abc def ghi jkl)和arr = ["abc", "def", "ghi", "jkl"]在哪些情况下应该使用%w？在上面的例子中，我需要一个数组["abc", "def", "ghi", "jkl"]。哪种方式是理想的:前者(使用%w)还是后者？

问何时使用%w？
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